Suspected cause for my case:

  • Vivo android phone use “randomized MAC address” when connected to WiFi
  • My house have main router + mesh router
  • I do IP Binding with Mac address
  • Combination above caused the issue.

Solution:

  1. On android, in respective connected WiFi setting, change Privacy to “Use device MAC” 

  2. Go to router > LAN > DCHP and remove any previous binding with your phone name
  3. Off Wifi on phone, go to another router, on wifi on phone, connect to it
  4. Fixed

RegardsMatthew